Lily of the Valley (Convallaria majalis) is an aggressively spreading perennial known for its fragrant, bell-shaped flowers and resilience. This durable groundcover propagates through underground stems called rhizomes, which feature pointed growth buds known as pips. While the plant’s hardiness allows it to be moved almost any time, summer presents significant physiological stress. Transplanting during this period of active growth and high heat is far from ideal, but success is possible with a meticulous approach and dedicated aftercare.
Understanding Optimal Timing and Summer Stress
The most favorable time for moving Lily of the Valley is during its dormant period, either in late fall after the foliage dies back or in early spring before new growth emerges. During dormancy, the plant’s metabolic demands are minimal, allowing it to dedicate energy to root establishment. Summer, conversely, is a period of peak activity where the plant actively transpires large amounts of water through its leaves to cool itself.
Disrupting the root system during warm weather immediately compromises the plant’s ability to absorb needed water, leading to rapid desiccation. This imbalance between water loss from the leaves and diminished water uptake from damaged roots is known as transplant shock. To conserve moisture, the plant closes the stomata on its leaves, which can lead to leaf overheating and reduced photosynthesis. This often results in scorched or yellowed foliage, meaning moving the plant now requires intensive measures to mitigate this shock.
Site Preparation and Pre-Move Hydration
Success in a summer move begins several days before the plant is lifted. Lily of the Valley thrives in partial to full shade, so the new location must be shielded from intense midday and afternoon sun, a major source of heat stress. The soil should be well-drained and enriched with organic matter, such as compost, to help retain consistent moisture while preventing waterlogging.
Dig the new planting hole two to three times wider than the estimated root ball, but only as deep as the root mass. In the days leading up to the transplant, deeply saturate the ground around the original clump with water. This pre-hydration ensures the plant is fully turgid and that the soil is moist and cohesive. This helps the delicate root ball hold together during the digging and transfer process, significantly reducing the initial shock when the roots are severed.
Executing the Summer Transplant
The physical act of moving the plant must be executed quickly and efficiently, preferably during the coolest part of the day, such as early morning or late evening. Using a sharp spade or garden fork, begin digging a wide circle four to six inches away from the clump to capture the maximum number of rhizomes and roots. Since Lily of the Valley spreads via shallow rhizomes (pips), a wide, shallow excavation is more effective than a deep one.
Carefully leverage the entire clump out of the ground, working to keep the root ball as intact as possible. Minimizing root disturbance is key, as damage reduces the plant’s capacity for immediate water absorption. Immediately transport the entire soil-root mass to the prepared hole and set it down. Replant the pips at the exact same depth they were growing previously; burying them too deep can lead to rot, while planting them too high will cause them to dry out.
Immediate Post-Transplant Care
Immediately after setting the plant, backfill the hole with the amended soil and initiate saturation watering. Pour water slowly and deeply over the entire area until the soil is thoroughly soaked. This helps settle the earth and eliminate air pockets around the roots. Air pockets are detrimental because they prevent direct contact between the roots and soil moisture.
For the first week, a strict and consistent watering schedule is required, often meaning watering daily or twice daily during heat waves. The soil must remain consistently moist, but not waterlogged, to encourage the formation of new, fine root hairs. Provide temporary shade for the first seven to ten days using a shade cloth or a makeshift structure. This prevents leaf scorch and minimizes transpiration stress. Closely monitor the foliage for signs of stress, such as wilting or browning leaf edges, which indicate the plant is struggling to absorb enough water.